Sanborn had a problem on its hands. The town of 1,200 in O’Brien County in extreme northwest Iowa had outgrown its Carnegie Library, which was built in the early 1900s and measured only 20 by 40 feet. In 2007, the city wanted to build a new library on the same site. But what to do about the historical gem?

Enter Sanborn Preservation, an organization that had formed just two years earlier and had, as president Fay Schall terms it, “more determination than cents.” The group had been working on turning an old hardware store in Sanborn into a...